Tool for finishing gear teeth



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UNITED STATES PATENTYOFFICE CHARLES H. SCHURR, 101 CLEVELAND, OHIO, ASSIGNOR TO THE LEE S-I BRADNEB COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO TOOL FOR FINISHING GEAR TEETH Application filed January 5, 1227. Serial No. 159,092.

This invention relates to finishing tools for as in Fig. 1. The chamfers 13, 14 of Fig. 1 gear teeth or the like. are plainly shown in Figs. 2, 3 and 4, as are The invention relates particularly to-finishalso the chamfers 15, 16 on the other ends of ing tools which are themselves of gear form, the teeth. The chamfers 13, 14, 15 -and 16 5 and which finish .the working faces of gear may be formed on the teeth by any suitable 55 teeth or the like while running in mesh theremethod or means, but I prefer to grind them with. i by a generating grinding machine. I

One of the objects of my invention is to When grinding the faces 11 and 12 of the provide an improved finishing tool in general gear teeth 1, and the chamfers 13, 14, 15, and .of ear form. 16, any suitable means or method may be em- 60 nother object is toprovide a finishing ployed, but when grinding them in the pretool suitable for use in carrying out the gear ferred manner by means of generating gear finishing method disclosed in my Patent No. grinders as above mentioned, I prefer to 1,642,179, Sept. 13, 1927. employ the method described in my co-pend- 15 Other objects will be apparent. mg appllcation, Serial No. 49,282, filed Au- The invention is fully disclosed in the folgust 10, 1925. According to that method the lowing description and accompanying drawgear-to-be-ground, in. this case the tool, is ings in which, given a rollin movement into and out of Fig. 1 is a view of a part of a tool of gear engagement with the planular face of a form embodyingmy invention, showing the grinding wheel. The gear orv gear tool rolls longitudinal ends of the tool teeth on one on a pitch circle thereof and the rotational side or face of the tool; 7 axis thereof describes a plane. The rotary Fig. 2 is an elevational view of a tool tooth planular faced grinding wheel is positionally inone form, taken from the, plane 22 of adjustable about an axis perpendicular to Fig. 1; said plane to adjust the helical angle at which 75 Fig. 3 is a cross-sectional view taken from it grinds. In producing a toolof the present the plane 3,3 of Fig. 1; invention, the grinding wheel may first be Fig. 4 is a partial sectlonal View, taken adjusted to zero helical angle and the faces 11 from the plane 4'4 of Fig. 1; of the teeth may be ground by rolling the Figs. 5 to 12 inclusive, are views similar gear or tool as above described. The tool to Fig. 3 showing modifications; may then be turned end for end and the faces Figs. 13 and'14 are views similar to Fig. 4 12 ground. The planular face of the grindshowing modifications. ing wheel may then be adjusted to a suitable My invention is disclosed as applied to the helical angle and helical tooth faces such as finishing of gear teeth and when so applied, 1 the faces 13 may be ground on each of the 85 prefer the form shown in Figs. 1 to 4 incluteeth and will constitute chamfers. The tool sive. The gear form tool, Fig. 1, has teeth may then be reversed end for end and in a 11, the faces 11 and 12 of which are accurate like manner helical faces 15 constituting to a high degree as to profile, spacing around chamfers may be ground. The planular face 40 the gear, and concentricity. I prefer to proof the grinding wheel may then be adjusted duce such teeth by rou hing them out in any 'to the same or similar helical angle opposite well known and suita le manner and then to the first helical angle in the sense of right finishing them by grinding on a generating and left hand and helical faces 14 may be grinder, but other methods may be employed. ground constituting vchamfers. The gear The ends of the-teeth, as viewed in Fig. 1, are may then be reversed end for end and helical then chamfered along their curved edges as at faces 16 maly1 be ground constituting cham- 13, 14. In Fig. 1, the chamfers appear upon fers. The c amfers13 and 15 therefore may 7 one end only of the teeth, but the other ends be, as illustrated in Figs. 1 to 4 inclusive,

not shown may similarly be chamfered, and fragmentary portions of the opposite faces if viewed as in Fig. 1, would appear the same, of a helical gear tooth which is, say, right 100 hand; and similarly the chamfers 14 and 16 may be fragmentary portions of the opposite faces of a left hand'helical gear tooth.

The tips or extreme outer portions of the teeth, radially considered, terminate in tip surfaces 10 and preferably these tip surfaces are not chamfered where they intersect the end surfaces of the teeth; the c amfers 13, 14, 15 and 16 thus extend all the way out to the tip surface, (and do not stop short thereof as they would if the tip surfaces were chamfered), and therefore may be coextensive with the curved side faces of the tool teeth, thus providing a working chamfer on the tool long enough to work over the whole working face of the work gear teeth.

The exact profile of the chamfers, as viewed in Fig. 3, may be different in different cases in accordance with the different conditions met in carrying out the method in which the tool is used, such conditions for instance as the structure of the metal of the work gear to be finished, its composition, hardness, etc., the amount of metal to be dealt with on the sur- 9, and this figure represents a chamfer so obtuse that it is substantially at right angles to the longitudinal direction of the tooth, that is it has the maximum obtuseness possible or practicable.

In Fig. 13 a modification is shown in which the obtuseness of the chamfer is substantially that of Fig. 12. In this modification the face of the tool is recessed or cut away as at 5-5, leaving raised portions 66. The working portions of the tool teeth may be renewed by grinding the faces 7--7 of the tool in a plane or substantially in a plane. The elevated portions 66 and recessed or cut away portions 55 may also be employed with the preferred form of Figs. 1 to 4 inclusive above described, when it is desired to renew the chamfers 13, 14 and 15, 16 thereof, and when repeated renewal makes it desirable to remove some of the end or ends of the tool tooth; for example, in Fig. 3 if the chamfers 13, 14 have been renewed, say by grinding, until they lie in positions represented by the lines 88, it may be desirable to grind off or faces to be finished of the Work gear teeth otherwise remove the end of the tooth to the when they are left over-size by the roughingplane indicated by the line 9.

out operation, etc., the rate of feed of the tool with respect to the work gear teeth longitudinally, the fineness of the resulting finish desired, etc. In this connection, the chamfer may have any of the forms shown in Figs. 3, 5 to 12 inclusive.

In Fig. 3 the chamfers 13, 14 and 15, 16 are on opposite ends of the tool tooth. In Fig. 5, the chamfers 15, 16 are placed intermediate of the ends. With this form, relatively thin work gears may be finished without having to move the tool and work gear relatively over the entire width of face of the tool, that is, over the entire longitudinal length of the tool teeth, but at the same time the tool can be relatively thick and have teeth of relative- 1y great length for strength. In Figs. 1 to F inclusive, two sets of chamfers 13, 14 and 15, 16 are provided,- in which forms the tool is adapted to work the gear teeth in both directions longitudinally, passing over them two or more times. In the forms, Figs. 6 to 12 inclusive, chamfers on only one end of the tool tooth are shown, and such tools are intended to finish the gear teeth in one passage thereover, or by repeated passes in the same direction. In Fig. 6, by having the reduced portion 4 intermediate of the ends of the tool tooth, the working portion of the tool tooth will run out free from the work gear teeth with relatively small longitudinal movement. In Fig. 7 a chamfer is shown of approximately the same degree of obtuseness as the chamfers of Figs. 1 to 6 inclusive- In Fig. 8, a less obtuse chamfer is shown. In Fig. 9, .a more obtuse chamfer is shown. In Fig. 10 the chamfer is curved convexly. In Fig. 11, the chamfer is curved concavely. In Fig. 12, the chamfer is even more obtuse than in Fig.

In the modification shown in Fig. 14, one end of the tooth has the chamfer 16, and the other end has the chamfer of Fig. 12.

My invention is not limited to the particular modifications shown. My invention embraces in its scope many forms of tool not shown which are in general of gear form,'and are suitable or adaptable to finish gears.

My invention is not limited in its application, to tools for finishing gears. The method of my above mentioned application for/example, is as shown therein, applicabl to shapes other than circular and to parts other than gears, and the invention of the present application embraces in its scope tools suitable for finishing all such and similar articles. In the claims therefore the expression in general of gear form is to be taken as meaning a tool which has such form that it meshes with the article which it finishes in the general manner of one gear meshing with another; or that the tool has teeth or other projections and grooves or recesses which fit or are conjugate to corresponding grooves or recesses and teeth or projections on the article being finished and with which it in consequence runs in mesh while finishing it.

My invention is applicable to the gear finishing method disclosed in my Patent No. 1,642,179., above referred to in which the gear to be finished and the tool are run in mesh with each other and fed axially relatively to each other as described therein, but my invention is not limited to use with this method.

In the claims, I refer to the axial end faces of the teeth of the tool of my invention and these faces will be understood to be the faces defining the extent of the teeth in the direction of the gear axis.

I claim:

1. A finishing tool for gears or the like, in general of gear form, the teeth of which have end surfaces and curved side faces and which are chamfered on the edges formed by the intersection of said surfaces and faces.

2. A finishing tool for gears or the like, in general of gear form, the teeth of which have end surfaces and curved side faces and which are chamfered on those edges only which are formed by the intersection of said surfaces and faces. I

3. A finishing tool for gears or the like, in general of gear form, the teeth of which have end surfaces, curved side faces and tip surfaces, edges at the intersections of the end surfaces with the side faces, and edges at the intersections of the end surfaces with the tip surfaces, and of these edges, the former only being chamfered.

4.. A gear re-working tool, in general of gear form and having gear form teeth some of which 'at'the longitudinal termination of the curved faces thereof are chamfered to provide working edges adapted to displace and correctively redistribute the material composing the tooth faces of the gear-to-beworked when the tool is rolled in mesh with the gear and concurrently fed longitudinally over the length of the gear teeth.

5. A gear re-working tool, in general of gear form and having gear form teeth some of which are provided each with a spur tooth face portion and a helical tooth face portion, the two face portions intersecting in a working edge adapted to displace and correctively redistribute the material composing the tooth faces of the gear-to-be-worked when the tool is rolled in mesh with the gear and concurrently fed longitudinally over the length of the gear teeth. t

6. A gear re-working tool, in general of gear form and having gear form teeth some of which are provided each with a spur tooth face portion and a plurality of helical tooth face portions, the helical portions intersecting the spur portion in a plurality of working edges adapted to displace and correctively' redistribute the material composing the tooth faces of the gear-to-be-worked when the tool is rolled in mesh with the gear and concurrently fed longitudinally over the length of the gear teeth.

7. A gear re-working tool, in general of gear form and having gear form teeth some of which are provided each with a plurality of spur tooth 'face portions and a plurality of helical tooth face portions, the spur portions being intersected by certain ones of the helical portions in a plurality of working edges fed 1llongitudinally over the length of the gear teet 8. A toothed tool in general of gear form some of the teeth of which are provided each with a working edge,the shape and position on the tooth of which are determined by the intersection of an involute spur tooth face and an involute helical tooth face successively produced on the tooth.

9. The method of producing a tool of gear form and provided with working edges on the teeth thereof adapted to displace and redistribute the material of the working faces of the teeth of a gear when rolled in mesh therewith and concurrently fed axially thereover which includes producing tool teeth having side faces and axial end faces intersecting in edges and then removing some of the material of the tooth along the edges formed by the intersections of the end and side faces.

10. The method of producing a tool of gear form and provided with working edges on the teeth thereof adapted to displace and redistribute the materlal of the working faces of the teeth of a gear when rolled in mesh therewith and concurrently fed axially thereover which includes producing tool teeth having curved side faces and axial end faces intersecting in curved edges and then removing some of the material from the curved edges to thereby form other faces intersecting the said curved faces and end faces.

11. A toothed tool in general of gear form,

the teeth of which have side faces and axial end. faces joined along a surface portion disposed inwardly with respect to the edge which would be formed by the said end and side faces if produced to-an edge of intersection.

12. The method of producing a tool in general of gear form, which includes producing tool teeth having side and axial end faces intersecting in edges and then removing some of the material from said faces adj acent said edges.

13. The method of producing a tool in neral of gear form, which includes producmg tool teeth having each a side face and an ax1al end face intersecting in an edge and then removing some of the material of said faces adjacent and along said edge.

14. The method of producing a tool in neral of gear form, which includes producmg tool teeth having side and axial end faces intersecting in edges and then removing the said edges.

In testimony whereof, I have hereunto signed my name.

CHARLES H. SCHURR.

adapted to displace and correctively redistribute the material composin the tooth faces of the gear-to-be-worked w en the tool is rolled in mesh with the gear and concurrently 

